AQA GCSE Biology Biology Paper 2 (Higher), June 2025: Question 9

9 marks · High Demand difficulty · Extended Answer

Analyse data regarding Type 2 diabetes prevalence, calculate mean Hb-G percentage change from a graph, and evaluate drug trial methods and drug effectiveness.

Practise this question

Question

Question 9 consists of three parts. Part 9.1 displays Figure 10, a grouped bar chart showing the percentage of people with Type 2 diabetes across three age categories (21–44, 45–64, and Over 64) split into healthy weight, overweight, and obese groups, asking for two conclusions. Two clinical investigations are described measuring the percentage of haemoglobin with glucose attached (Hb-G): Investigation 1 gives a table (Table 4) showing drug A starting at 9.2% and ending at 7.6% after 12 weeks; Investigation 2 gives a line graph (Figure 11) plotting mean change in percentage Hb-G over 24 weeks for a placebo and drug B (reaching -0.65% at 12 weeks). Part 9.2 is a multiple choice calculation of drug B's Hb-G after 12 weeks starting from 8.3%. Part 9.3 is a 6-mark extended evaluation of the methods used and the usefulness of drugs A and B.
Question text

09 Type 2 diabetes is a condition that has become more common in recent years.

09.1 Scientists recorded the percentage of people of different ages who had

Type 2 diabetes.

The people were in different weight categories:

• healthy weight

• overweight

• obese.

Figure 10 shows the results.

Figure 10

Give two conclusions from the results in Figure 10.

[2 marks]

Two groups of scientists investigated the use of different drugs to treat

Type 2 diabetes.

In both investigations, the scientists measured the percentage of haemoglobin with

glucose attached (Hb-G).

*29*This showed the long-term concentration of glucose in the blood.

Investigation 1:

The scientists injected drug A into 175 patients with Type 2 diabetes once each

day for 12 weeks.

Table 4 shows the results.

Table 4

Mean value

At start At 12 weeks

Percentage (%) of haemoglobin with glucose attached (Hb-G) 9.2 7.6

Investigation 2:

631 patients with Type 2 diabetes took one tablet containing drug B each day.

A control group of 630 patients took a placebo tablet each day.

The scientists measured the Hb-G in each patient’s blood at the start of the

investigation and at 6-week intervals up to 24 weeks.

Figure 11 shows the results.

Figure 11

09.2 For the patients treated with drug B the mean percentage of Hb-G at the

start was 8.3%.

What was the mean percentage of Hb-G after 12 weeks for the patients treated with

drug B?

[1 mark]

Tick ( ) one box.

0.65% 0.75% 7.65% 8.95%

09.3 In a person without diabetes, the Hb-G value is between 4.5% and 6%.

When treating patients with Type 2 diabetes, doctors think that an

Hb-G value <7% is acceptable.

Evaluate:

• the methods used in the investigations

• the usefulness of drug A and drug B for controlling Type 2 diabetes.

[6 marks]

Extra space

Mark scheme

Show the mark scheme The mark scheme provides answers for Question 9. For 9.1 (2 marks): percentage of people with Type 2 diabetes increases with age (1 mark), and increases with body mass/weight/obesity (1 mark). For 9.2 (1 mark): 7.65%. For 9.3 (6 marks): a 3-level response grid with indicative content comparing methods (administration route, dose not stated, study duration, presence of placebo/control, frequency of intermediate readings, sample sizes) and evaluating the usefulness of drug A and drug B (both lower Hb-G levels to similar extents, drug A reduces more, neither achieves <7%, drug B increases after 18 weeks, lack of side-effect information).

Question 9

AO /

Question Answers Extra information Mark

Spec. Ref.

allow converse

09.1 AO3

allow answers in terms of 4.5.3.2

likelihood of having / getting

(Type 2) diabetes

(percentage of people with Type allow more old people have 1

2) diabetes increases with age (Type 2) diabetes

(percentage of people with Type allow more obese people have 1

2) diabetes increases with (Type 2) diabetes

increased (body) mass / weight allow (percentage of people with

type 2) diabetes increases with

obesity

AO /

Spec. Ref.

09.2 7.65% 1 AO3

4.3.1.9

4.5.3.2

AO /

Question Answers Mark

Spec. Ref.

Level 3: A judgement, strongly linked and logically supported by

09.3 5–6 AO3

a sufficient range of correct reasons, is given.

4.3.1.9

4.5.3.2

Level 2: Some logically linked reasons are given. There may

3–4

also be a simple judgement.

Level 1: Relevant points are made. They are not logically

1–2

linked.

No relevant content 0

Indicative content

allow ‘investigation 1’ for drug A and ‘investigation 2’ for drug B

throughout

Methods

Methods are not comparable because:

• different methods are used to administer the drugs - injection

(drug A) and pill (drug B)

or drug A acts more quickly (than drug B)

• dosage for drug A and drug B might differ (as dosage is not 27

stated)

• drug A and drug B are tested for different time periods

or B is given for a longer period (24 weeks) (than A - 12 weeks)

• placebo / control only included when testing drug B

• only drug B has intermediate readings

or fewer readings were taken when testing drug A

• different sample sizes were used

or greater sample size used when testing drug B

(A = 175, B = 631 / 1261)

• different scientists carried out each investigation

• no double-blind trial for drug A

Methods may be similar because:

• neither drug trial was double-blind

• quantitative tests in both trials

• (relatively) large sample size used for both drugs

Usefulness of drug A and drug B

allow ‘blood glucose’ for Hb-G throughout

o both lower Hb-G (levels)

o both lower Hb-G to similar levels

o drug A reduced Hb-G more than drug B

o neither drug reduced Hb-G to an acceptable value (<7%)

o Hb-G increases after 18 weeks with drug B

o no information on side effects for either drug

o no information on the trend for drug A

For Level 1, details about the method or usefulness of the drugs

must be given.

For Level 3, details about the method and usefulness of the drugs

must be given.

Total Question 9 9

How to answer it

Type 2 Diabetes Risk Factors & Clinical Drug Trials

📋 What this question tests

This question assesses your ability to interpret epidemiological data, read graphs with negative axes, carry out clinical trial calculations, and provide an extended evaluation of experimental design:

  • Data interpretation: Identifying trends between age, body mass/obesity, and Type 2 diabetes prevalence.
  • Graph analysis & calculations: Reading negative changes on a line graph to determine final percentage values.
  • Scientific method & evaluation (6-marker): Comparing clinical trial methodologies (placebos, sample sizes, administration routes, trial duration) and assessing the clinical efficacy (Hb-G reduction) of two drugs.
Question 09.1 • [2 marks]

Drawing Conclusions from Demographic Data (Figure 10)

Identifying two distinct trends linking diabetes, age, and weight category

✅ Mark Scheme Model Answers

Any two independent conclusions from:

  • The percentage of people with Type 2 diabetes increases with age (or older people are more likely to have diabetes). [1 mark]
  • The percentage of people with Type 2 diabetes increases with body mass / weight / obesity (or obese people are more likely to have diabetes). [1 mark]

🧠 Exam Technique: Describing Trends

When a bar chart has two grouped independent variables (here, Age range and Weight category), you need one conclusion for each variable:

  • Age effect: Look across age brackets (21–44 vs 45–64 vs Over 64) for each weight group → bars get taller.
  • Weight effect: Look across categories within each age group (healthy vs overweight vs obese) → bars get taller.

❌ Common Errors

  • Just quoting data without concluding: Writing "In over 64s it is 35%" is a reading, not a conclusion.
  • Only mentioning one variable twice: Stating "Obese people have more diabetes than overweight" and "Healthy people have the least" only scores 1 mark because both describe weight.
  • Confusing Type 1 and Type 2 diabetes: Diabetes in this context is strictly linked to lifestyle/risk factors.
Question 09.2 • [1 mark]

Reading Graphs & Calculating Hb-G Concentration

Finding the mean percentage of Hb-G after 12 weeks for Drug B

📐 Step-by-Step Calculation

  1. Find starting value: Given in the question = 8.3% .
  2. Read change from Figure 11 at 12 weeks:
    Follow the x-axis to week 12. Move down to the line for Drug B.
    Value on y-axis = -0.65% (Mean change in percentage of Hb-G).
  3. Calculate new percentage:
    8.3% + (-0.65%) = 8.30 - 0.65 = 7.65%

✅ Correct Answer

Tick box: 7.65% [1 mark]

Other distractors:
  • 0.65% (Misreading the change as the final absolute value)
  • 0.75% (Reading the lowest point at 18 weeks as an absolute value)
  • 8.95% (Adding the 0.65% reduction instead of subtracting it: 8.3 + 0.65)
Question 09.3 • [6 marks]

Extended Evaluation: Trial Methods vs Drug Usefulness

Evaluating methodology and clinical usefulness of Drug A and Drug B

Levels of Response Mark Scheme:
  • Level 3 (5–6 marks): A reasoned judgement is given, strongly linked and logically supported by a sufficient range of points comparing both methods and the usefulness of both drugs.
  • Level 2 (3–4 marks): Some logically linked reasons given discussing method and/or usefulness. May include a simple judgement.
  • Level 1 (1–2 marks): Relevant points made about method OR usefulness; no logical links or conclusion.

💡 Evaluation Points: Methods

Why methods are NOT directly comparable / flaws:

  • Administration route: Drug A is an daily injection; Drug B is an oral tablet (tablets are easier for patient compliance; injections act faster).
  • Sample size: Drug A had 175 patients; Drug B had 631 patients (Drug B trial is larger & more reliable).
  • Control group / Placebo: Drug B used a placebo control group (630 patients); Drug A had no placebo group.
  • Duration & monitoring: Drug A tested for 12 weeks only (start and end); Drug B tested over 24 weeks with readings every 6 weeks.
  • Dosage: Dosages of the active ingredients were not specified.

💡 Evaluation Points: Usefulness

How well the drugs control blood glucose (Hb-G):

  • Overall effect: Both drugs lower Hb-G levels to similar values around 12 weeks (Drug A to 7.6%, Drug B to 7.65%).
  • Magnitude of drop: Drug A caused a larger reduction (9.2% → 7.6% = -1.6%) than Drug B (8.3% → 7.65% = -0.65%).
  • Acceptable target: Neither drug achieved the doctors' acceptable target of <7% Hb-G (non-diabetic is 4.5–6.0%).
  • Long-term efficacy: Drug B loses some effectiveness after 18 weeks (Hb-G rises from week 18 to 24); we have no data past 12 weeks for Drug A.
  • Missing data: No data on side effects or cost for either drug.

🧠 Top-Grade Model Structure for 6 Marks

  1. Paragraph 1 (Evaluate Methods): Compare the trials. Note that Drug B has a much stronger study design because it includes a large control group taking a placebo and tracks progress over 24 weeks, whereas Drug A lacks a placebo and has fewer participants.
  2. Paragraph 2 (Evaluate Usefulness): Compare blood glucose reduction. State that Drug A reduces Hb-G by a greater amount (-1.6% vs -0.65% at 12 weeks). However, highlight that neither drug reached the acceptable <7% target. Also mention that Drug B starts to lose effectiveness after 18 weeks.
  3. Paragraph 3 (Justified Conclusion): Make a clear decision. E.g., "Overall, Drug B has better trial reliability and is easier to take (tablet), but Drug A is more potent at lowering glucose over 12 weeks. Neither drug is fully effective as neither brings Hb-G below the 7% threshold."

❌ Examiner Warnings: Where Marks are Lost

  • Omitting a final conclusion: To reach Level 3 (5–6 marks), an explicit judgement is compulsory.
  • One-sided answers: Writing exclusively about the methods and ignoring how well the drugs worked (or vice versa) caps your answer at Level 1 or 2.
  • Missing the target context: The prompt specifies that doctors consider Hb-G <7% acceptable. Top students explicitly state: "7.6% and 7.65% are still above the 7.0% acceptable limit."

Topics

Biology · B3: Infection and Response · B5: Homeostasis and Response

Question and mark scheme from the AQA GCSE Biology examination, Biology Paper 2 (Higher), June 2025. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.